Aim and Objective: The prospective study was conducted to assess the role of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in healing of soft tissue after the surgical extraction of mandibular-impacted third molars. The main objective of the study was to compare clinical parameters and especially the postoperative pain, swelling, interincisal distance, wound dehiscence, dry socket, soft tissue healing, and infection. Materials and Methods: 300 patients having impacted mandibular third molar were included in this study. They were selected on the OPD basis at the Department of Oral and Maxillofacial Surgery. Patients were divided into Group A treated with PRP and Group B treated with PRF. Result and Conclusion: The study indicates faster healing with no untoward reaction on PRP and PRF group. Platelet concentrates especially PRF in extracted third molar socket give excellent enhancement in wound healing with lesser postoperative complication.

Third molar extraction is the most common minor surgery performed in oral and maxillofacial surgery department. Healing of wounds histologically proceeds generally in three phases: catabolic period, proliferative phase, and reparation and reorganization phase.[1] Platelet-derived growth factors (PDGFs) mainly have effect on proliferation phase. Regenerative potential of platelets was introduced in 1974, and Ross et al. were among the pioneers who firszt described a growth factor from platelets which have been shown to stimulate the mitogenic response in the periosteum for bone repair during normal wound healing.[2],[3],[4]

In 1997, platelet-rich plasma (PRP) was first introduced through an article entitled “platelet gel; an autologous alternative to fibrin glue with applications in oral and maxillofacial surgery.” They also assumed “through activation of the platelets within the gel and the resultant release of growth factors, enhanced wound healing should be expected.”[1],[2],[3],[4],[5]

Choukroun's platelet-rich fibrin (PRF) is a fibrin matrix in which platelet cytokines and cells are entrapped. They are released a certain time and can act as a resorbable membrane.[6] Gassling et al. and Khiste and Tari have shown that PRF is suitable to breed human periosteal cells in vitro. It can be used for bone tissue engineering applications.

This study compares the effectiveness of PRP and PRF in wound healing of extracted mandibular third molar.

Materials and Methods

A total of 300 patients reporting to Department of Oral And Maxillofacial Surgery, Hitkarini Dental College and Hospital, Jabalpur Madhya Pradesh, who were willing for extraction of impacted mandibular third molar and who satisfied the inclusion and exclusion criteria were selected. Patients were divided into Group A treated with PRP and Group B treated with PRF.

Patient aged between 18 and 30 years of either sex, having asymptomatic impacted mandibular third molars with mild to moderate difficulty (Pederson index), without any systemic disorders, who did not have any abusive habits, and female patients who were not using oral contraceptives were included in this study. Patient with infection at the site of surgery, having substance abuse, any hematological problems or deficiency diseases, and who were not willing for extraction were excluded.

Preparation of the patient

All the patients were briefed about the surgical procedure and autologous PRP/PRF harvesting. A written informed consent was obtained from all the patients. Institutional ethical committee clearance was obtained to conduct the study.

Under aseptic techniques, 10 ml of intravenous blood was drawn from the antecubital region using 10 ml disposable syringe and blood was transferred to acid citrate dextrose tubes. Then, the blood was centrifuged using a “soft” spin (2400 rpm for 10 min). After that, another sterile tube (without anticoagulant) is taken, and the supernatant plasma containing platelets was transferred. Then, the tube was centrifuged using a “hard” spin (3600 rpm for 10 min) to get the platelet concentrate. The upper 2/3 is platelet-poor plasma (PPP) and lower 1/3 is PRP. Platelet pellets are formed at the bottom of the tube. PPP was removed, and the platelet pellets were suspended in a 2–4 mL of plasma by gently shaking the tube.

Preparation of platelet-rich fibrin

The tube with 10 ml of whole blood was kept in the centrifuge machine and centrifuged at 3000 rpm for 15 min. Out of the three layers formed after centrifugation, the middle layer (PRF) was extracted. The others two layers (PRP and red blood cell) were discarded.

Surgical technique

Patients were asked to gargle with chlorhexidine mouthwash 1 min before starting the procedure. Draping and painting of the surgical area is done. The nerve blocks given were inferior alveolar nerve block, lingual nerve block, and long buccal nerve block. 2% lignocaine hydrochloride with 1:1:80000 adrenaline is used as an anesthetic agent. Average 3 ml solutions were used. The ward's incision was made in all the cases with blade no 15, full thickness mucoperiosteal flap raised for adequate exposure. Guttering of bone was done at 10,000 rpm to 30,000 rpm with stainless steel round (No-8) and straight fissure bur (No-712) under constant copious saline irrigation. Sectioning of the tooth was done if required. Elevators and forceps were used to remove the tooth. The surrounding bone was smoothened using bone file and the wound was irrigated with 20 ml of normal saline. Then, the obtained PRP gel was placed into the Group A extraction socket and PRF gel into Group B extraction socket and then socket was sutured using 3-0 mersilk simple interrupted suture.

Facial measurements were made based on the method described by Gabka and Matsumara. It required surface soft tissue marking of 5 points on the ipsilateral side: Lateral canthus of eye, Corner of the mouth, Pogonion, Angle of the mandible, and Tragus.

Three arbitrary lines were constructed using these points as references [Figure 1]:

The arithmetic sum of the 3 measurements was used to determine the facial swelling at any point of time.

Mouth opening

Mouth opening before and after the surgical procedure was measured as the interincisal distance using a metallic ruler.

Dry socket

Dry socket is a very painful condition caused by loss or necrosis of the blood clot formed at the extraction site within 24–72 h after extraction thus exposing the underlying bone. The presence or absence of dry socket was evaluated clinically on day 3.

Infection

Clinical evaluation was done to rule out the presence (+) of infection at every visit during the study period.

Wound dehiscence

Wound dehiscence is a surgical complication in which the wound ruptures along the surgical sutures. Dehiscence was assessed clinically as absent (−) or present (+) on postoperative day 3 and 7.

Soft tissue healing

Healing index of Landry, Turnbull and Howley - the soft tissue healing of the extraction wound was assessed on postoperative day 7 by evaluating 5 parameters – tissue color, presence or absence of bleeding on palpation, presence or absence of granulation tissue, epithelialization of incision margin, and presence or absence of suppuration. The healing index ranged from 1 to 5, 1 being very poor healing and 5 being excellent healing.

Wound dehiscence and dry socket were present in 3 (30.00%) cases in control group and 1 (10.00%) case in PRP group. None of the individuals in PRF group were observed with wound dehiscence at postoperative day 1 and day 7. Chi-square test showed no significant difference between the groups for wound dehiscence (χ2 = 4.038, df = 2, P > 0.05). Infection was present in 1 (10.00%) case in control group. None of the individuals in PRF and PRP groups were observed with infection. Chi-square test showed no significant difference between the groups for infection (χ2 = 2.069, df = 2, P > 0.05) [Graph 4].

One of the emerging topic in dentistry is the use of PRP, PRF for the repair and regeneration of the hard and soft tissue after various surgery.[1],[2],[3],[4],[5],[6] PRP was introduced as the first generation of platelet concentrate. A classical blood sample has about 5% platelets while PRP had 95% platelets. The procedure required blood collection with anticoagulant. Later on, artificial polymerization of platelet was done using bovine thrombin. PRP required an expensive equipments and additives to reach the final product.[7],[8]

Choukroun et al. was the first who developed PRF in France. This technique requires neither anticoagulant nor bovine thrombin (nor any other gelling agent). It is nothing more than centrifuged blood without any addition. A blood sample is taken without anticoagulant in 5 mL tubes which are immediately centrifuged at 3000 rpm for 10 min.[9],[10]

The success of this technique depends on two factors: first, the speed of blood collection and second, transfer to the centrifuge. Upon contact with the tube glass, and it takes a minimum of a few minutes of centrifugation to concentrate fibrinogen in the middle and upper part of the tube. Quick handling is the only way to obtain a clinically usable PRF clot.

Dohan et al. proved a slower release of growth factors from PRF than PRP and observed better healing properties with PRF. They all concluded that PRF offers many advantages, it decreases the frequency of intra- and post-operative bleeding at the donor and the recipient sites, facilitates more rapid soft tissue healing, aids in the initial stability of the grafted tissue at the recipient sites, may promote rapid vascularization of the healing tissue by delivering growth factors and in combination with bone replacement materials, induces regeneration.[13],[14]

Our study included 200 female and 100 male patients who were the age group of 18–30 years, having impacted mandibular third molar. All the 300 patients were asymptomatic before the surgery.

All the patients were treated with extraction of impacted mandibular teeth with placement of PRP on 100 extracted sockets, PRF on 100 extracted sockets, and rest 100 extracted sockets left without any platelet concentrates on a random selection process.

Postoperatively pain was assessed using VAS score. On 1st, 3rd, and 7th day, VAS scores in control group were significantly higher than PRP and PRF groups. There was no significant difference between PRP and PRF groups.

Postoperative swelling was evaluated. On the 1st and 3rd day, swelling in control group was significantly higher than PRP and PRF groups. There was no significant difference between PRP and PRF groups for swelling. On 7th day, both sides, there is no significant difference between the groups for swelling.

On comparing the interincisal distance, on 1st, 3rd, and 7th day, maximum interincisal distance in PRP and PRF groups were significantly higher than control group. There was no significant difference between PRP and PRF groups for swelling.

In our study, only 30 patients (control – 20 and PRP – 10) had wound dehiscence and dry socket, and 10 patients from control group had postoperative infection.

PRF in the form of a platelet gel can be used in conjugation with bone grafts. It has several advantages, like it promotes wound healing, bone growth and maturation, and hemostasis. It also imparts better handling properties to graft materials. It can be used as a membrane too.

Conclusion

Autologous PRP and PRF can be used as an adjunct to promote wound healing in mandibular-impacted third molar extraction socket.

The present study done on 30 patients clearly indicates a definite improvement in the soft tissue healing and faster regeneration after the surgical removal of mandibular-impacted third molar. It showed excellent soft tissue healing and lesser postoperative complication on PRP and PRF group compared to control group.

Preparation of autologous PRP and PRF in dental office is not a time-consuming procedure; it is easy to use and beneficial to patient and as well as clinician. It is cost-effective also. It contains growth factors especially PDGF and TGF-β. PRP and PRF in dental clinic reduce bleeding and rapid healing, which holds promise for further procedures. Most importantly, this autologous product eliminates the chances of immunogenic reactions and disease transmission.